The present invention concerns a motor vehicle door latch with a locking mechanism with a catch and a pawl. The latch further demonstrates a triggering lever, a blocking lever and two activation levers. The blocking lever prevents rotation of the triggering lever and thus opening of the locking mechanism, if at least one of the activation levers is activated with an activation speed which exceeds a determined threshold. This occurs during an accident, for example, in particular a lateral impact.
The door latch interacts with a locking bolt or equivalently with a locking clip. Usually, the door latch is arranged in the motor vehicle door and the locking bolt on the motor vehicle chassis, but a reverse arrangement is possible. During closure of the motor vehicle door the locking bolt engages into a recess of the catch. Then the catch rotates around its rotational axis. Consequently, the locking bolt is trapped in the catch and thus an opening of the motor vehicle door is prevented. The pawl interacts with the catch by preventing rotation of the catch and thus releasing of the locking bolt. By activation of a handle which is arranged inside or outside of the motor vehicle door, the engagement of the pawl into the catch is released and the catch can be rotated into a position in which the locking bolt can leave the recess and the motor vehicle door can thus be opened.
In the present document the term “door handle” or “handle” means that any handle on the door of a motor vehicle, the activation of which causes the activation of a pertaining activation lever of the motor vehicle latch.
The activation of a door handle is transferred to a pertaining activation lever of the motor vehicle latch, by means of a Bowden cable, for example. In the event of a lateral impact, great accelerations act on the motor vehicle. However, a door handle demonstrates a certain mass inertia. Consequently, the lateral impact can lead to activation of the door handle. However, the activation is jerky with an activation speed which considerably exceeds activation speed caused by a human. This is also the case when the door handle catches on an object. On the basis of the activation speed of the door handle and thus the pertaining activation lever, it can be distinguished whether the locking mechanism will be made inoperative, i.e. if ultimately a rotation of the catch into its release position for the locking bolt will be prevented. An activation speed limit which is defined, for example, as a limit angle speed of an activation lever acts as a threshold for this distinction.